Summary
A medRxiv preprint analysing 8,741 female participants older than 70 reports that associations between menopause hormone therapy, cognition and brain structure differed by treatment formulation and APOE ε4 status. Among APOE ε4 carriers, estradiol-based therapy was linked to more favourable cognitive and imaging measures than conjugated equine estrogens.
A medRxiv preprint reports that the relationship between menopause hormone therapy (MHT), late-life cognition and brain structure varied according to both the therapy’s formulation and whether participants carried the APOE ε4 genetic variant.
The analysis included 8,741 female participants older than 70. Its results suggest that estradiol-based MHT was associated with more favourable neurocognitive outcomes than conjugated equine estrogens among APOE ε4 carriers. Brain-imaging data from a subset of 930 participants showed a similar pattern: APOE ε4 carriers using estradiol-based therapy had associations with higher brain volume and cortical thickness, along with less white-matter damage.
The study is a preprint, meaning the findings have been posted before peer review. It reports associations rather than results from a prospective treatment intervention.
What the analysis found
The researchers examined cognitive outcomes in relation to MHT formulation and APOE ε4 status. The abstract describes the cognitive findings as formulation- and domain-specific, indicating that the relationship was not uniform across all types of hormone therapy or all measured cognitive areas.
The clearest contrast in the report involved estradiol-based therapy and conjugated equine estrogens among APOE ε4 carriers. Estradiol-based MHT showed the more favourable association in this group. The neuroimaging analysis, available for 930 participants, found a consistent structural pattern in the same direction, including greater volume, thicker cortex and less white-matter damage.
Brain volume, cortical thickness and white-matter measures are structural imaging outcomes. They can provide information about brain health, but they are distinct from measures of daily functioning or a clinical diagnosis of dementia. The supplied abstract does not report the size of the observed differences or identify particular brain regions.
Why formulation and APOE ε4 matter
MHT is not a single exposure. Different formulations can have different pharmacokinetic properties—how a substance is absorbed, distributed and processed by the body. The researchers argue that failing to distinguish between formulations may help explain why previous research on MHT and cognitive ageing has produced mixed findings.
APOE ε4 is a genetic variant associated with Alzheimer’s disease risk. In this analysis, its presence appeared to modify the relationship between MHT formulation and both cognition and brain-imaging measures. That interaction is important because it suggests that an overall estimate for “hormone therapy” could conceal different patterns across genetic-risk groups.
The authors say the findings support approaches to menopause care and research that account for both formulation and genetic risk. The results are relevant to how future studies define hormone exposure and analyse cognitive outcomes, while the study population itself consisted of participants older than 70.
How to interpret the evidence
The report analysed data available through the National Alzheimer’s Coordinating Center and examined associations in an older population. Its conclusions are therefore best understood as evidence of relationships between MHT formulation, APOE ε4 status and late-life cognitive or imaging measures, rather than as evidence that one formulation caused a particular brain outcome.
The imaging results came from only a subset of the full sample, and the supplied abstract does not provide details such as effect sizes, treatment duration, doses or the full set of adjustments used in the analysis. The findings also come from a medRxiv preprint and require assessment alongside peer-reviewed and interventional evidence before they can guide formulation choices for individual patients.